Barack Obama's re-election may have dominated the headlines, but the 2012 election will also be remembered for the remarkable number of progressive firsts it ushered through. Across the nation new ground was broken in drug legalisation, gay marriage and diversified representation, especially for women.

1. First openly gay female senator

Tammy Baldwin, who became the first openly gay US senator, winning in Wisconsin. Photograph: Andy Manis/AP

In Wisconsin, Democratic representative Tammy Baldwin became the first openly gay US senator when she defeated former governor Tommy Thompson in a hotly contested race. The two candidates spent about $65m on the campaign, making the contest the most expensive in state history.

"I didn't run to make history," Baldwin told her supporters in her acceptance speech. "I ran to make a difference."

In addition to being the nation's first gay senator, Baldwin is Wisconsin's first female senator. State assemblyman Mark Pocan, a Democrat who is also openly gay, will succeed Baldwin in her House seat.

2. First states legalise recreational marijuana

A woman lights a marijuana cigarette, sometimes known as a 'joint'. Photograph: Jockmans/Rex Features

In a major coup for drug reformers, Colorado and Washington became the first states to legalise the possession and sale of marijuana for recreational use. Several states, including Colorado and Washington, already have medical marijuana laws on the books, but 2012 will no doubt remain a seminal year for American stoners since it suggests that the public, at least in some states, is on their side.

It's worth noting that both states' reforms are in direct conflict with federal policies, which classify cannabis as an illegal narcotic. As Colorado governor John Hickenlooper, a Democrat who opposed the measure, cautioned in a statement: "Federal law still says marijuana is an illegal drug, so don't break out the Cheetos or Goldfish too quickly."

3 & 4 & 5. First Buddhist, first Asian American woman and first Japanese-born senator

Mazie Hirono will be the first female Senator from Hawaii, the first Asian-American woman elected to the Senate, the first Senator born in Japan, and the nation's first Buddhist Senator. Photograph: AFP/Getty Images

In Hawaii, Democrat Mazie Hirono made history when she beat former governor Linda Lingl to make Hirono the first Buddhist, first Asian American woman and first Japanese born senator-elect. Hirono was born in Fukushina, Japan and practices the Jodo Shinshu tradition of Buddhism. She was first elected to Congress in 2007 to represent Hawaii's 2nd District. Hirono previously served 14 years in the Hawaii state legislature and was the state's lieutenant governor for eight years.

6. First Hindu in Congress

In Hawaii, 31-year-old Tulsi Gabbard was elected as the first Hindu member of Congress. Gabbard, who served in combat in Iraq, is of Samoan descent and her mother embraced the Gaudiya Vaishnava tradition. Photograph: AFP/Getty Images

Hawaii also broke new ground in the House. In the Aloha state's 2nd Congressional District, Democrat Tulsi Gabbard defeated Republican opponent Kawika Crowley, making Gabbard the first Hindu in Congress.

Gabbard was born in American Samoa, but has spent most of her life in Hawaii. In 2002, when she was just 21, she joined the Hawaii state legislature.

Gabbard, who was raised by a Catholic father and a Hindu mother, chose to embrace Hinduism when she was a teen. Since she relies upon the Bhagavad Gita as her main source of scripture, she said that when she's sworn in this January she'll take her oath of office on the sacred text.

7. Montana and Colorado are the first states to pass anti-personhood laws for corporations

Cover of Super Pac strategy document outlining plan to highlight Barack Obama's links to Jeremiah Wright, via the New York Times

Corporations are not people, at least that's what voters in Montana and Colorado said they believe in two separate state resolutions passed overwhelmingly on Tuesday. Although the resolutions won't change any laws, they are the first statewide initiatives supported by voters calling for corporate personhood reform.

The idea of corporate personhood, which was upheld by the supreme court's 2010 Citizens United ruling, freed corporations and unions to spend unlimited sums of money (think Super Pacs) on independent political campaigns often without disclosing the names of the donors.

Previously reform groups leaned on state legislatures and city councils to pass resolutions calling for the overturn of the controversial court ruling.

8. New Hampshire is the first state to have all women in top elected official positions

A voter checks her ballot in Balsams Hotel in Dixville Notch, New Hampshire Photograph: Jessica Rinaldi/Reuters

New Hampshire elected women to all of its most prominent elected positions. The state's governorship, two Senate seats and two House seats will all be occupied by women in January.

Democrats Carol Shea-Porter and Ann McLane Kuster beat two Republican men to represent the state in the House. They will join senators Jeanne Shaheen, a Democrat, and Kelly Ayotte, a Republican, who weren't up for re-election. Rounding out the new matriarchy is governor-elect Maggie Hassan, a Democratic state senator, who will replace Democrat John Lynch.

Of course, this is hardly the end for men. Women remain woefully underrepresented across the nation. So much so that in Congress it wasn't until 2011 that a women's bathroom was installed off the House floor.

9. First time gay marriage passed as a ballot measure

After years of disappointment at the polls, gay marriage activists saw a handful of big wins on Tuesday. For the first time ever voters in three states – Maine, Washington and Maryland – approved ballot initiatives allowing same-sex unions.

Other states with gay marriage laws like New York, Connecticut and Vermont had their gay-marriage reforms pushed through by the courts or legislators. The three popular vote victories suggest a sea-change in the public's perception of gay marriage.

Activists also scored a victory from voters in Minnesota where voters turned back a proposed constitutional amendment that would have prohibited same-sex marriage if it were approved by law.

10. First time that House Democrats do not have a white male majority

Democratic leader and member of the US House of Representatives, California, Nancy Pelosi. Photograph: Stan Honda/AFP/Getty Images

For the first time House Democrats do not have a white male majority. With eight races still be determined, Bloomberg predicted that the new balance of the legislative body would be striking. White men will sit in about 90% of the Republican seats, while just 47% of Democratic seats will have white men.

• This article was amended on 12 November 2012. The original said Tulsi Gabbard was raised by a Catholic father and a Buddhist mother, and chose to embrace Buddism when she was a teen. This has been corrected to say a Hindu mother, and that Gabbard embraced Hinduism when she was a teen.